Electrical relay



Dec. 22, 1931 N. c. SHAW ELECTRICAL RELAY Filed Dec. 24, 1930 Insulation INVENTOR.

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BY Qua-1f Fly. 2.

ATTORNEY.

Patentecl Dec. 22, 1931 uNiTED STATES PATENT OFFICE NOBLE C. SHAW, OF SWISSV'ALE, PENNSYLVANIA, ASSIGNOR TO THE UNION SWITCH & SIGNAL COMPANY, OF SWISSVALE, PENNSYLVANIA, A CORPORATION OF PENN- SYLVAN IA ELECTRICAL RELAY Application filed December 24, 1930. Serial No. 504,459.

My invention relates to electrical relays.

I will describe one form of electrical relay embodying my invention, and will then point out the novel features thereof in claims.

In the accompanying drawings, Fig. 1 is a vertical sectional view showing one form of relay embodying my invention. Fig. 2 is an isometric view of the contact member C forming a part of the relay shown in Fig. 1.

1 Fig. 3 is a fragmentary bottom view of a portion of the relay shown in Fig. '1.

Similar reference characters refer to similar parts in all three views.

Referring first to Fig. 1, the reference character A designates the top plate of a relay.

This top plate is made of some suitable insulating material, such as a phenol condensation product and carries an electromagnet B. The cores 1 of this electromagnet, only one of which is shown in the drawings, pass through the top plate A and terminate, on the other side of the top plate," in pole pieces 2. Secured to the pole pieces 2 by means of screws 3 is a bracket 4. An armature 5 of magnetizable material, such as soft iron, is

pivotallysupported on pivot pins 6 carried by bracket'et, an'd'is arranged to be drawn upwardly toward the pole pieces 2 when magnet B is energized. Attached to the underside of armature 5' is a support 7 of suitable insulating material, such as a phenol condensation product, which support in turn, carries a flat contact finger 8. When magnet B is deenergized, armature 5 drops down under the influence of ravity, andfinger 8 then engages a fired back contact 9 which is fastened to top plate'A by meansof a binding post 10. When magnet B is energized, however, armature 5 is drawn upwardly into engagement with a core pin 11, as illustrated in the drawings, and contact finger 8 then engages a fixed front contact member C embodying my invention, which contact member T will now describe.

Referring now also to Figs. 2 and 3, the contact memberiC comprises a holder 12 of suitable electro-conductive material, such as brass, having a substantially horizontal upper portion 12 and an integral depending portion 12 The upper portion 12 fits snugly between parallel ribs formed on the underside of the top plate A, as best seen in Fig. 3, andis provided with a hole 12 which receives the shank 13' of a bolt 14* forming part of a terminal post 14 mounted on top plate A. It will be apparent, therefore, that the bolt 14 securely fastens the holder to the top plate, while the ribs 15 on the underside of the top plate prevent the holder from turning. The depending portion 12 of the holder 12, as here shown, is inclined at an angle of approximately 120 withthe upper portion 12*, and is provided at its lower end with two spaced parallel plates 12 and 12 These plates are joined at one edge by an integral web 12 and are provided with registering openings 12 and 12*, respectively, as illustrated in Fig. 1. A fiat contact block 17 preferably of graphite, is interposed between the plates 12 and 12 of holder 12. This contact block, as *here shown, is rectangular in shape. A screw 18 passes through the openings 12 and 12 in the plates of holder 12 and also through a hole 17 a in block 17 The holes 12 and 12 as Well as the hole 17 a are preferably of such size as to make a snug fit with the screw 18. A nut 19 is screwed onto the threaded end of screw 18, and the screw and nut are locked in place by lock washers 20 and 21, respectively.

In order to prevent the contact block 17 from turning in the holder 12 in the event that the screw 18 should become loosened for any reason, it is desirable that theweb 12 should engage the side of the contact block throughout the vertical length of the web. This would be difficult to accomplish if the web were made flat, because in manufacturing a holder of the type described it is desirable to provide a rounded corner having a radius approximately equalto the thickness of the web at those portions of the web where the web joinseach of the plates 12 and 12 to prevent the metal from cracking during bending, and these rounded corners prevent the web from engaging the edge of the concentrally disposed longitudinally extending reentrant portion 12 which is of such a depth that when the contact block is in place this reentrant portion engages, throughout its entire length, the adjacent edge of the contact block. It will be apparent, therefore, that with the webconstructed in this manner, the block will besecurely held in its proper aligned position in the holder even. though the nut 19 should become loosened sufficiently so that the contact block is 'no longer securely clamped between the plates. The reentrant portion 12 also serves to add a degree of flexibility to the web which permits the parallel plates 12 and .12 to be drawntogether to engage the contact 'block when the nut is tightened,

It will be "seen from an inspection of Fig.

that the :holder extends from the top plate at such an angle that the lower corner 17" of the contact block .makes=contact with the contacting portion of .the finger 8-when the the holder, so thatzthe'upper side of the block as shown in .Fig. 1 becomes the lower side, the corner 17 may be brought into substantially .theysame position in which the corner l7 ,isshown in tlie drawings, and this corner will then be in the proper position to make contactwith @the contacting ,portion of the :finger 8 when magnet B i-s-energized. The dimensions of the contact block *17 are such that wear on either corner will noteflectthe other Icorner, andit follows that in a relay provided with a holder embodying myxinvention, the

:useful life of the'contact block will be twice that ofthe contact'block ordinarily employed in relays of the type described.

One advantage of a contact member embodying .my invention as .that at as simple in design and therefore inexpensive .to manufacture.

Another advantage of a contact member embody-ing my invention is that improper alignment of the contact block is positively prevented. This is important because relays of the type :described are frequently employed in rail-way signaling systems where misalignment of a contact 1 might result in .a

dangerous signalindication.

Although I have herein shown and describedon'ly-one form of electrical relay-em- :bodyingmy invention, it is understood that various changes and modifications mayibe 'm'ade therein within the scope dfthe appended claims without departing from the spirit and scope of my invention.

Havingthus described my invention, what .I claim is:

.1. In combination, accontact holder having spacedparallel plates joined by a web, and a contactzblockclampedbetweensaidplates,said

webbeingprovided with a reentrant'portion entrant portion, and a contactblock clamped between said plates in such manner that said reentrant portion engages one edge of said block and maintains said block in the proper position in said holder.

3. In combination, a-contact holder having spacedparallel plates provided with registering openings, said plates being joined by an integral web provided with a reentrant portion, a screw passing through said openings, and a fiat substantially rectangular contactblock clamped between said plates by means of said screw in such manner that said reentrant .portion engages one edge of said block and holds said block in the proper position between said plates.

4:. In combination, an electrical contact structure for cooperation with a movable contact finger, said structure comprising a contact holder having a depending portion provided at its lower end with two parallel plates connected by an integral web, and a fiat contact block clamped between said plates, said web being crimped to form a reentrant portion which engages one side of said block for maintaining said block in proper alignment with respect to the contactingsurface of said movable contact finger.

5. An electrical contact structure for a relay comprising a contact holder having a depending portion provided at its lower end with two parallel plates formed with registering openings, a screw extending through said openings, a flat substantially rectangular contact block having a hole to accommodate said screw with a tight fit, said contact block being clamped between said plates by said screw, and an integralrelatively flexible web connecting said plates, said web being provided with a reentrant portion which engages one edge ofsaid block for maintaining-said block in a fixed position between said plates even though said screw becomes loosened.

, 6. An electrical contact structure comprising a contact holder-having a first flat portion provided with a hole adapted to receive means for featuringthe contact structure to an electrical device, a depending portion integral with said first portion and provided at its lower end with two spaced parallel plates hav- :clamping said block between said plates, said reentrant portion being so designed that it engages one edge of said contact block and pre vents said block from turning about said screw between said plates.

7. The combination with a relay top plate and a contact finger movable in a path which is fixed with respect to said top plate, of a contact structure comprising a contact holder attached to said top late and having a depending portion provi ed at its lower end with two spaced parallel plates joined by an integral web formed with a reentrant portion, said plates being provided with registering openings, a screw passing through said openings, and a fiat substantially rectangular block clamped between said plates by means of said screw in such manner that said reentrant portion engages one edge of said block and prevents said block from turning between said plates, said holder being so disposed with respect to said finger that one lower edge of said block is normally in the proper position to cooperate with the contacting portion of said finger but that by reversing said block in said holder the opposite lower edge of said block may be brought into the proper position to cooperate with the contacting portion of said finger, whereby the life of said block is doubled.

In testimony whereof I affix my signature.

NOBLE C. SHAW. 

